Rewrite menu code

Big change. Rewritten whole menu code.
* improved compatibility to original actionsMenu.
* easier definition
* actions can now be added to menu without definition in theme source
* href and args can now be auto-generated
* cfg value memodump_menu_def can bring in additional menu_def entries
* headers can now be defined without menu_def, add things like '= title
=' directly to menu list.